The lunch was also hosted by real-estate developer Donald Trump and Bill Palatucci, a top political adviser to Mr. Christie, according to the invitation.

Mr. Christie is the chairman of the Republican Governors Association and has raised money for GOP candidates across the nation. Mr. Palatucci said the event Wednesday wasn’t affiliated with the RGA and was among numerous fundraisers Mr. Christie planned for fellow Republicans this year.

Mr. Branstad is seen as a favorite to be re-elected in Iowa, which hosts an early Republican primary in the 2016 election. Mr. Christie has said he is considering running for president.

Mr. Palatucci declined to say how much money was raised at the event.

A spokesman for Mr. Branstad didn’t immediately return a call for comment. An assistant to Mr. Trump said he wasn’t immediately available for comment.